Photographic materials are generally composed of an insulating support and photographic layers. As a result, photographic materials often became electrostatically charged due to contact friction between the surface thereof and other materials of either the same or different composition, or due to peeling of the protecting coat or the like from the surface of the photographic material during the manufacture or use thereof. Accumulated static charges are disadvantageous in that the light-sensitive emulsion layer of the photographic material is exposed upon discharge of the accumulated static charges prior to development to result in undesirable spots or arborescent or feathery streaks in the developed photographic material. Such spots or streaks, called static marks, greatly reduce the commercial value of the photographic film or cause the same to lose all commercial value. Since static marks become apparent only after the photographic film has been developed, the problem is extremely troublesome. Additionally, as a secondary problem, the accumulated static charges also result in the adhesion of dust to the surface of the processed or non-processed photographic film, to thereby make uniform coating difficult.
The occurrence of static marks increases with the use of higher sensitive photographic materials and accelerated development thereof. Recently, in particular, photographic materials are more often processed under severe conditions, namely high-speed coating, high-speed picture-taking and high-speed automatic development. As a result, the generation of static marks in photographic materials processed in such a manner is further augmented. Moreover, with the recent increased use of photographic materials, adhesion of dust to the photographic material is being addressed as an important contamination problem in this technical field.
In order to overcome the problem of accumulated static charges, antistatic agents may be added to the photographic material. However, the antistatic agents generally employed in technical fields other than the photographic field are not directly applicable to all photographic materials. Antistatic agents which can be employed in a photographic material must be compatible with the characteristics of the photographic material. Particularly, antistatic agents for use in photographic materials necessarily have an excellent antistatic ability, do not adversely affect photographic characteristics such as sensitivity, fogging graniness and sharpness, do not adversely affect film strength, do not adversely affect the anti-adhesive property (i.e., adhesive resistance) of the material, do not fatigue the processing solutions used for processing of the photographic material, do not stain conveyer rollers of an automatic processor used to process the photographic material and do not lower the adhesive strength between the constitutive layers of the photographic material. Thus, there are many limitations in the application of antistatic agents to photographic materials. Static charges may be controlled by increasing the electroconductivity of the surface of the photographic material, such that the static charges on the surface thereof are dissipated prior to discharge of the accumulated charges.
Accordingly, a number of methods for elevating the electroconductivity of the support and surface layer of photographic materials have heretofore been proposed and a number of moisture-absorbing substances and water-soluble inorganic salts, as well as certain surfactants or polymers have been utilized for this purpose.
Above all, surfactants are important for imparting antistatic properties to a photographic material. For example, the anion, betain or cation surfactants described in U.S. Pat. Nos. 3,082,123, 3,201,251, 3,519,561, 3,625,695, West German Patents 1,552,408, 1,597,472, JP-A-49-85826, JP-A-53-129623, JP-A-54-159223, JP-A-48-19213, JP-B-46-39312, JP-B-49-11567, JP-A-51-46755, JP-A-55-14417 (the terms "JP-A" and "JP-B" as used herein mean "unexamined published Japanese patent application" and "examined Japanese patent publication", respectively); and the nonion surfactants described in JP-B-48-17882, JP-A-52-80023, West German Patents 1,422,809, 1,422,818, Australian Patent 54,441/1951, have been proposed for use as antistatic agents.
However, the above described surfactants are useful only in specific types of film supports, as well as to specific photographic compositions constituting the photographic materials. Accordingly, the above described surfactants do not satisfy the above-described requirements, and are extremely difficult to apply to photographic materials.
On the other hand, JP-B-51-9610 proposes the use of phenolformalin condensate-ethylene oxide adduct polymers as providing an excellent antistatic property, even when the polymers are incorporated into a photographic material along with other coating agents. However, the above-described method also results in contamination of the photographic material and the processing solutions.
JP-A-53-29715 discloses a photographic material containing a particular anionic surfactant and nonionic polyoxyethylene surfactant. However, the material disclosed therein also results in contamination of the processing solutions and conveyer rollers.
JP-A-64-68751 discloses a photographic material containing a polyphosphagen compound. However, the compounds illustrated therein still do not overcome the above described problems
Recently, reduction in the use of rinsing water has been desired for preservation of the environment or for economization of water resources, as well as for simplification of the processing apparatus. Reduction in the amount of the replenisher employed is desirable for reducing the processing cost, and an increase in the concentration of the processing solutions is desirable for shortening the processing time. Under such processing conditions recently employed in the photographic field, the above-described problems of contamination of the processing solution and generation of photographic uneven images are pronounced, such that the development of techniques for overcoming these problems are becoming much more important.